Question

Tìm x:

\(\frac{72-x}{7}\)- \(\frac{x-70}{9}\)

Answer 1

72-x nhân9 -   x -70 nhân7

= 648 - 9x - 7x-490 

=158-2x

Answer 2

Ta có \(\frac{72-x}{7}-\frac{x-70}{9}=\frac{\left(72-x\right).9}{7.9}-\frac{\left(x-70\right).7}{9.7}=\frac{648-9x}{63}-\frac{7x-490}{63}\)

\(=\frac{648-9x-7x-490}{63}=\frac{158-2x}{63}\)

Answer 3

=\(\frac{158-2x}{63}\)sorri mình hơi lười